When you CHANGE THE AMOUNT of a solid, that does not affect the equilibrium. However, you are not changing the amount of CaCO₃. You are changing the temperature, and that DOES affect the reaction. The effect is to shift it to the products, so CaCO₃ gets used up.

If you asked what would be the change in CO₂ if the amount of CaCO₃ was increased, the answer would be no change, because changing a solid does not affect the position of the equilibrium. However, an increase in CO₂ will increase the amount of CaCO₃, because an increase in CO₂ will shift the react to the reactants.

In other words, solids CAN BE AFFECTED (as can water in aqueous reactions) by changes in other aspects of an equilibrium. However, if you change the amount of solid (or water in an aqueous reaction), that cannot affect the other aspects of the equilibrium.